CSSTidy (https://github.com/csstidy-c/csstidy)

CSSTidy Portions Copyright:
   * Florian Schmitz <floele@gmail.com>
   * Thierry Charbonnel
   * Will Mitchell <aethon@gmail.com>
   * Brett Zamir <brettz9@yahoo.com>
   * sined_ <sined_@users.sourceforge.net>
   * Dmitry Leskov <git@dmitryleskov.com>
   * Kevin Coyner <kcoyner@debian.org>
   * Tuukka Pasanen <pasanen.tuukka@gmail.com>
   * Frank W. Bergmann <csstidy-c@tuxad.com>
   * Frank Dana <ferdnyc@gmail.com>

   The CSSTidy codebase is itself is Available under the LGPL 2.1

    CSSParser csst;

    css_file = CSSUtils::file_get_contents(argv[1]);

    // valid css levels are "CSS1.0", "CSS2.0", "CSS2.1", "CSS3.0" 
    csst.set_level("CSS3.0");

    // do the actual parsing
    csst.parse_css(css_file);

    // check for any parse errors
    std::vector<std::string> errors = csst.get_parse_errors();

    // check for any parse warnings
    std::vector<std::string> warnings = csst.get_parse_warnings();

    // check for any parse information messages
    std::vector<std::string> infos = csst.get_parse_info();

    // get any @charset without having to walk the csstokens list
    std::string cset = csst.get_charset();

    // get all @import without having to walk the csstokens list
    std::vector<std::string> imports = csst.get_import();

    // get any @namespace without having to walk the csstokens list
    std::string ns = csst.get_namespace();

    // enum token_type
    // {
    //    CHARSET, IMPORT, NAMESP, AT_START, AT_END, SEL_START, SEL_END, PROPERTY, VALUE, COMMENT, CSS_END
    // };

    // struct token
    // {
    //    token_type type;
    //    int pos; // position in input string
    //    int line; // line number in input string
    //    std::string data;
    // };

    // now walk the sequence of parsed tokens
    // if you know the location of the token you want in the sequence (starting with 0)
    // simply pass start_ptr in get_next_token set to a valid starting point in the token sequence

    CSSParser::token atoken = csst.get_next_token();

    while(atoken.type != CSSParser::CSS_END) {

        std::string ttype = csst.get_type_name(atoken.type);

        std::cout << "Pos: " << atoken.pos
                  << " Line: " << atoken.line
                  << " Type: " << ttype
                  <<"  Data: " << atoken.data << std::endl;

        atoken = csst.get_next_token();
    }

    // serialize back to CSS
    std::string cssout;
    cssout = csst.serialize_css();